Battery charger



FIG. 1 is a front, top, and right side perspective view showing my new design for a battery charger in full lines, with the broken line matter being for illustrative purposes only and forming no part of the claimed design;

FIG. 2 is a left elevational view thereof;

FIG. 3 is a bottom plan view thereof; and,

FIG. 4 is a rear elevational view thereof. 

The ornamental design for a battery charger, as shown and described. 